Conference 7.286::space

    Good job they decided to allow deep-space nuclear power. It would be a
    shame to have to put the Sun out :-)
    
    Dave Hazel

    I heard two items in the news that utilize nuclear power in space. 
    First there was an article in the New York Times that described
    Russia's efforts in designing a nuclear powered rocket.  The Russians
    are much more advanced in metallurgy than the US.  They've developed
    some metals that could be used to withstand the high temperatures that
    would be generated by a nuclear powered rocket.  Russians have been
    developing nuclear powered rockets for some time.  NASA is apparently
    very interested and are working with the former Soviet space agency.
    
    The second item is that Grumman has unveiled plans for a nuclear
    powered rocket that will go to Mars.  
    
    In both the Russian and American rockets, the ships will be launched
    from Earth using conventional rockets and then when the ship is far
    enough away it will switch to nuclear power.

    Any information on thrust generated? Impulse?
    
    
    Gregg

Is the Grumman thing really Timberwind, the DOD nuke propulsion that was just
(slightly) unveiled?

If so, I believe that AvWeek said it had an impulse of 200 seconds or so.  Don't
remember the thrust.

Burns

RE: .4
    
�If so, I believe that AvWeek said it had an impulse of 200 seconds or so.
    
    I thought impulse has the same units as momentum, which is,
    mass*length/time.

    The units that I am talking about is actually
    
    pounds_force * seconds/pounds_mass
    
    That is, how much total acceleration can it give a craft for a given
    mass that it will add to the craft.  The two different kinds of pounds
    are usually erroneously cancelled out to yield seconds.  I believe
    this is called "Specific Impulse" (or at least the units match what
    AvWeek calls specific impulse.  There is also a "Total Impulse",
    but I'm less sure about that one.
    
    I'm home with the AvWeek now, and I got the number wrong.  Here is the
    right set of numbers:
    
    Timberwind has 75,000 pounds of thrust, a 30:1 thrust-to-weight ratio,
    and 1000 sec. of specific impulse.

    If Timberwind is rated to produce 75,000 pounds of thrust, how much
    mass (Hydrogen?) does it require per second at rated thrust?
    
    Also, how does this compare with tradition chemical motors (solid and
    liquid) in terms of efficiency?
    
    				Cheers,
    				-Abdul-
    

    The info that Burns related in .6 is the total amount of published
    specs to date on Timberwind. There is supposed to be more made public
    soon.
    
    Most chemical propellant engines today produce impulses in the high
    200s with 300s possible with exotic additives (e.g. use liquid fluorine
    instead of LOX, beryllium instead of aluminum). I recall some figures
    being posted somewhere in this file.
    
    Specific impulse is one measure of efficiency, but to determine the
    efficiency of a vehicle using such an engine you need to know masses of
    the engines, tanks etc. If it has to operate in the atmosphere,
    propellant density becomes important too.
    
    However, a 3-4 times increase in specific impulse alone is enough to
    grab attention.
    
    gary

    Re. .6:
    
>   The two different kinds of pounds
>   are usually erroneously cancelled out to yield seconds.
    
    The cancellation is not erroneous. The units of the figure are seconds
    (from a dimensional analysis of the expression used to calculate it).
    So it _should_ be quoted as "specific impulse of X seconds". The error
    is in a reader assuming that this refers to time. It does not, though
    it is obviously easy to make the mistake of thinking that it does.
    
    Dave Hazel

re .9:

I disagree with you, though I may have misstated the reason earlier.  I
consider the cancellation erroneous because in the traditional use of our system
of measurements, pounds is a measure of both force and mass.  The two units are
only the same at the Earth's surface.  In fact there is a unit of mass in our
system, the Slug, which is seldom used.

The problem is that in deriving the expression for specific impulse, there is a
term which describes the mass of the engine/fuel.  Unfortunately it is specified
in pounds.  When you specify a mass in pounds, it can't be cancelled by a force
in pounds in dimensional analysis.  They are different units.

Now you could argue that the problem is not the cancellation of pounds, but
rather the fact that pounds were used instead of slugs in the first place, and I
suppose I would go along with that (with the proviso that if we are talking about
"should-haves", the ultimate is that we SHOULD HAVE used the metric system.

But anyway, I believe the correct measure of specific impulse in our system
should be something like pound-seconds/slug.

Burns

    Re. .10:
    
    The unit for specific impulse is still seconds when the SI system is
    used.
    
    Dave Hazel

    Well, as is true in many realms both of you are correct, but one more
    correct than the other:
    
    From Rocket Propulsion Elements:
    
     I = F/wdot
    
    	Where I is the specific impulse in pound of thrust per pound per
    second of propellant flow (Wdot).
    
    	f = thrust in pounds
    	wdot = weight flow rate in pounds per second
    
    
    Now, IMPULSE (often called total impulse) is the integral of the thrust
    F over the duration t. It can be defined as a function of specific
    impulse:
                t        t
    	Isubt = | F dt = |I * wdot dt
                0        0
    
     The units of Isubt are in pound seconds.
    
     in a footnote:
    
     "In equations.... care must be exercised to distinguish the concepts
    and terminology involving mass, weight, and gravity. In ordinary
    engineering practice, gravity variations are not important, and it has
    become common practice to use mass and weight quantities
    interchangeably. .........the  thrust of a rocket is really a function
    of the mass flow rate and not of the weight flow rate. Specific impulse
    with the units of seconds is defined here as a force (lb) divided by a
    weight flow rate (NOT a mass flow weight - GG); however it is really
    independent of gravity. In mass terminology, the quantity I would have
    the dimension of ft/sec and wouldbe numerically equal to the exhaust
    velocity, c."
    
    Does that clear it up? ;^)
    
    Gregg
                0        0

             Headline News
Internal Communications Branch (P-2) NASA Headquarters

  Tuesday, March 10, 1992  Audio Service: 202 / 755-1788

This is NASA Headline News for Tuesday, March 10, 1992 . . .

NASA is again scheduled to provide testimony to House of
Representatives committees this week.  The first hearing will be
by the House Subcommittee on Investigations and Oversight
(Chairman Howard Wolpe, D-Mich.) on the SP-100 nuclear power
system.  Office of Aeronautics and Space Technology Deputy Associate
Administrator Bob Rosen is scheduled to testify.  The hearing will
be on Thursday, March 12, at 9:30 am EST.  The next hearing will be
another House Joint Hearing by the Subcommittees on Space
(Chairman Ralph Hall, D-Texas) and Technology and Competitiveness
(Chairman Tim Valentine, D-N.C.) and the Armed Services
Subcommittee on Research and Development.  This hearing, which will
look into space launch systems, will take place Thursday at 1:30 pm
EST.  Both hearings are scheduled to be covered live on NASA
Select television.

Article: 628
From: [email protected] (THOMAS FERRARO)
Newsgroups: clari.news.gov.usa,clari.news.gov.international
Subject: U.S. to buy Russian space-age technology
Date: 28 Mar 92 05:13:15 GMT
 
	WASHINGTON (UPI) -- The administration, under pressure to
boost aid to the republics of the former Soviet Union, intends to buy
millions of dollars in previously secret Russian space-age technology.

	Officials said Friday the Hall thrusters and Topaz space power
unit would be used in the Strategic Defense Initiative, the ``Star
Wars'' system that Russian President Boris Yetlsin has said he wants
his nation to participate in. 

	In addition, Russian plutonium-238 would be used as a fuel for
NASA's space program, said White House press secretary Marlin Fitzwater. 

	Although the overall cost for the technology is relatively
modest, about $15 million, Fitzwater said the action underscores the
U.S. post- Cold War commitment to the republics and would be followed
by additional aid. 

	President Bush has under study a plan to step up assistance to
the republics, which is expected to be announced in mid-April, White
House officials said. 

	The officials, who requested anonymity, said Secretary of
State James Baker submitted the draft program to Bush earlier this
week and it was being reviewed by national security adviser Brent
Scowcroft. 

	The package is expected to include $1 billion to stabilize the
ruble, more humanitarian and technical assistance and a $12-billion
increase in the U.S. contribution to the International Monetary Fund,
officials said. 

	Bush has been criticized by members of Congress, by former
Presidents Nixon and Carter, and others for having thus far offered
inadequate aid to the CIS. 

	They contend that the newly emerging nations need major aid to
to stay on the road toward a free market and democracy. Failure to do
so, they warn, could lead to a collapse of the CIS and a return to
dictatorship. 

	Fitzwater, in announcing plans to purchase Russian technology,
also said the administration is working to remove import barriers on
non- military items. 

	``These transactions clearly signal our desire to normalize
trade relations with the new states,'' the press secretary said. 

	Fitzwater said all the technology purchases announced Friday
would be from Russia, which a national security official said had
agreed to sell ``because they need the money.'' 

	The press secretary announced that the administration will
authorize the purchase of an unfueled Topaz space nuclear reactor for
experimental use at the University of New Mexico. The unit will cost
about $8 million. 

	``This purchase will give us access to new technology at a
significantly lower cost than if we were to try to develop it
ourselves, '' Fitzwater said. 

	He said the administration will authorize the purchase of four
Hall thrusters, valued at $200,000 to $300,000. He said the devices
provide a means for using electric current to propell objects into
space, and offer ``possible applications for efficient orbital
transfers of satellites.'' 

	Fitzwater said the administration had approved a license
application for a private firm to proceed toward buying one of the
thrusters, but declined to immediately indentify the company. 

	He said the Energy Department has been authorized to enter
into discussions about Russia's offer to sell plutonium-238 to the
United States. Cost would be about $6 million. 

	Plutonium-238, an isotope not used in nuclear explosives, is
used as the fuel in radioistope thermonuclear generators. These
generators supply electricity on NASA space missions. 

	``This purchase will allow us to meet NASA schedules for
needed space power supplies economically, and without the need to
restart nuclear reactors to do so,'' Fitzwater said. 

Article: 42288
From: [email protected] (Nick Szabo)
Newsgroups: sci.space
Subject: More on Russian tech being purchased
Date: 29 Mar 92 08:35:56 GMT
Organization: TECHbooks of Beaverton Oregon - Public Access Unix
 
More info on the technology recently approved for purchase from Russia.  
 
Space Power Inc. is importing the Russian Topaz space nuclear reactor
into the U.S. for use in spy satellites, SDI battle stations, and
direct broadcast satellites.  SDIO is now leaning towards Topaz and
withdrawing funding for SP-100, leaving the latter funded only by DOE
($35 millon/yr) and NASA ($10 million/yr) at a level insufficient to
complete the program. 
 
The electric rocket engine, or "Hall thruster", is similar to our own
magnetoplasmadynamic (MPD) engine but tested to much longer lifetimes
than our own, whose filaments burn out after a few seconds. 
 
Not much public info is available (if anyone finds more, let us
know!), but the info I have shows the Russian engineers claiming a 60%
efficiency converting electrical to kinetic energy, and shooting for a
specific impulse of 1,000-2,000 s.  In contrast, the best known
chemical rocket upper stage engine, the RL-10 used on Centaur, has a
specific impulse of 440 s.  Thrust may be 25-200 N, compared to 5e-6 -
0.5N for ion electrostatic engines and 147,000 N for RL-10. 
 
If those numbers are achieved, it would make a dandy engine both for
stationkeeping and for deep space missions like the lunar/Mars/asteroid 
minprobes, CRAF, Cassinni, Rosetta comet sample-return, Mars rover/sample 
return, and volatile extraction missions.  It might also be an improvement 
for getting satcoms to GEO.
 
In magnetoplasmadynamic (MPD) rockets, an electric current is
transfered into a plasma.  The current carrying plasma interacts with
a magnetic field resulting in a Lorentz acceleration to expel the
plasma.  My info lists argon as the propellant for U.S. versions of
this engine.  This is _not_ an ion rocket, which is lower thrust,
higher specific impulse, and works on different principles. 
 
The U.S. will also buy a small amount of plutonium for powering RTGs
of deep space probes such as CRAF, Cassinni, and Rosetta. It seems we
will soon run out of our own.... 
 
All for the price of $14 million, which would last the SSF project
people two and one-half days.  And you thought U.S.  space engineers
were underpaid.  :-) 
-- 
[email protected]  Public Access User --- Not affiliated with TECHbooks
Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81) 

Article: 42612
From: [email protected] (Nick Szabo)
Newsgroups: sci.space
Subject: U.S. commerce, government buy Russian engine
Date: 7 Apr 92 06:17:02 GMT
Organization: TECHbooks of Beaverton Oregon - Public Access Unix
 
More information on the Russian Hall effect electric rocket engines
has been released.  Fifty (50) of these "stationary plasma thrusters"
have flown in space on operational Soviet spacecraft for stationkeeping.  
They operate by ionizing xenon gas and accelerating that plasma with a 
magnetic field.  The following are on sale for c. $50-100K per unit: 
 
SPT-70
specific impulse: 1,600 s.
thrust: 0.009 lbs.
power: 660 watts
weight: 3.3 lbs.
design life: 3,500 hrs.
 
SPT-100
specific impulse: 1,600 s.
thrust: 0.018 lbs.
power: 1,350 watts
weight: ??
lifetime: 4,000 hrs.
 
U.S. government agencies have purchased four SPT-70 thrusters through
Space Power Inc., San Jose CA for a reported $200-300K.  Space
Systems/Loral, which makes commercial and government spacecraft, has
signed a joint venture and marketing agreement with Fakel Enterprises
in Kalingrad, Russia.  Loral says that the engines will reduce the
launch mass of their GEO spacecraft by 20%. 
 
A high-thrust version reportedly under development in Russia could be
used as an upper stage, doubling payload capability to GEO for current
launchers, and increasing payload capability to deep space (eg Mars,
asteroids, prograde short-period comets) by over a factor of three. 
 
Other U.S. government purchases through Space Power Inc. include a
Topaz-2 thermionic nuclear power system for $7.9 million and $6
million for plutonium (Pu-238 used for RTG batteries on deep space
missions, not Pu-239 used in weapons). 
-- 
[email protected]  Public Access User --- Not affiliated with TECHbooks
Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81) 

    Is the xenon gas carried at launch, or is it
    obtained as a fission decay product from the
    on-board reactor?
    

    re .17
    
    It's my guess that the Xenon would be carried at launch. Most Earth
    orbiting craft wouldn't have an on-board nuclear reactor (military ones
    possibly excluded).
    
    Nice idea if you can make it work.
    
    I don't think Xenon is produced by normal fission (Uranium) reactors? I
    don't know about Plutonium based RTGs? From the dim dark past I seem to
    recall that Uranium fissions to Barium and Krypton (also an inert gas
    but with lower atomic weight than Xenon). Perhaps if Radium were used
    in the RTGs, the Radon could be used instead of Xenon. One thing to
    look into is the rate at which gas is expelled (say for
    station-keeping) versus the rate of production from the nuclear
    process. Is enough gas produced?
    
    What are the properties of Xenon that make it suitable or desirable for
    use in this sort of thruster?

Article: 2551
From: [email protected] (UPI)
Newsgroups: clari.news.gov.usa,clari.tw.space,clari.tw.nuclear
Subject: Activists want to nuke space nuclear rocket
Date: 20 Jul 92 16:12:55 GMT
 
	WASHINGTON (UPI) -- An international group of scientists,
anti-nuclear activists, and environmentalists Monday announced they
will attempt to block further development of the Air Force's space
nuclear thermal rocket, as the Senate begins discussion on funding of
the defense budget. 

	Activists fear that nuclear reactors, which fuel the rockets,
will pollute Earth's atmosphere or endanger lives through an accident
similar to the Space Shuttle Challenger or an orbiting version of the
Chernobyl nuclear plant core meltdown in the former Soviet Union.
Both incidents occured in 1986.

	Michio Kaku, a physics professor at City University of New
York, said, ``Proposed space nuclear reactors could generate up to
twice the power of present nuclear power plants.'' 

	Kaku said NASA and the Air Force are interested in the nuclear
rocket because it is the most power for the money, or the highest
specific impulse. 

	Nuclear rockets would be used in deep space exploration by
NASA and for military uses, such as anti-ballistic missiles, through
the Air Force, said Steven Aftergood, a scientist with the Federation
of American Scientists. 

	The Strategic Defense Initiative Organization formerly ran the
space nuclear reactor project as the secret, black budget Timberwind
project and spent $130 million, Aftergood said.  The Air Force took it
over last year as the Space Nuclear Thermal Propulsion Program despite
a number of testing problems experienced by SDIO. 

	Aftergood said the Air Force expects to put in $700 million
for development through ground testing of the rocket. 

	The House recently tripled its funding for the project after
first zeroing it out, Aftergood said.  A Senate panel was to begin
discussions on the defense budget Monday. 

	Kaku said that nuclear reactors can be used to generate
electricity to run the rocket, for example in deep space exploration.
The current Galileo and Ulysses deep space missions have used nuclear
power systems, called RTGs, to run the instrumentation panels.  He
called these ``the foot in the door'' to get the public accustomed to
nuclear use in space. 

	In another type, the heat generated from a nuclear core can
directly produce propulsion or rocket thrust, which the military has
proposed using for ground-based anti-ballistic missiles and other
military uses, such as high powered lasers. 

	Kaku said the safety evaluations of the proposed nuclear
rocket are faulty because they do not take into consideration human
failure.  ``All nuclear accidents from the 1965 Fermi reactor through
Three Mile Island and Chernobyl have included human failure.'' Cascading 
sequence, where one or two things go wrong and each starts a chain 
reaction, have also contributed to accidents, he said. 

	A nuclear accident orbiting Earth could not be contained as
well as on Earth.  ``All radioactive emissions would be assimilated
into the atmosphere and into us,'' Kaku said. 

	The Global Network on Weapons and Nuclear Power in Space are
23 organizations from across the nation and Canada and England. 

Article: 15041
From: [email protected] (Henry Spencer)
Newsgroups: sci.space.shuttle
Subject: Re: A Fragment of Light Speed
Date: 13 Sep 93 17:45:23 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]> [email protected]
(Courtney Smith)  writes: 

>... fusion fragment rockets.
>Carvotta stated that an engineering group, funded by the
>Department of Energy, developed the concept for the rocket.
>Also, he stated that the rocket could travel 5% the speed of
>light.  What I was wondering was why the department of energy
>funds such projects?
 
DoE is the US government's nuclear-energy agency, remember?  They are
involved in most any US government project involving nuclear power,
and they have most of the US government's expertise in nuclear
technology. It's natural for them to spend a little bit of money
investigating possible advanced applications. 
 
Note, by the way, that this concept -- like most such -- is many years
away from actually being able to build flight hardware.  What DoE
funded was a little paper study, nothing more. 
 
>What use could possibly come about such as
>space travel possibilities.
 
Any propulsion system that can reach velocities like that would
(probably in a better-optimized form) put the solar system in our
hands.  As an interstellar drive such things are marginal -- you need
to reach 10-15% of the speed of light for even borderline interstellar
missions to be practical -- but for solar-system work it would be
marvellous. 
 
>Also, what other projects are currently underway that are comparable?
 
There are always a sprinkling of advanced studies underway.  None of
them, even the ones that are practical in the nearer term, have any
support for going further than paper. 
-- 
"Every time I inspect the mechanism     | Henry Spencer @ U of Toronto Zoology
closely, more pieces fall off."         |  [email protected]  utzoo!henry

Article: 15047
From: [email protected] (Paul Dietz)
Newsgroups: sci.space.shuttle
Subject: Re: A Fragment of Light Speed
Date: 13 Sep 93 23:08:45 GMT
Organization: University of Rochester
 
In article <[email protected]> [email protected] (Henry
Spencer) writes: 

>In article <[email protected]> [email protected]
(Courtney Smith)  writes: 
>>... fusion fragment rockets.
>>Carvotta stated that an engineering group, funded by the
>>Department of Energy, developed the concept for the rocket.
>>Also, he stated that the rocket could travel 5% the speed of
>>light.  What I was wondering was why the department of energy
>>funds such projects?
 
>interstellar drive such things are marginal -- you need to reach 10-15%
>of the speed of light for even borderline interstellar missions to be
>practical -- but for solar-system work it would be marvellous.
 
I think this is a bit confused.  The original reference to a "fusion
fragment rocket" is garbled.  There isn't anything commonly called a
"fusion fragment".  Instead, there is something called a "fission
fragment rocket,"  invented by Chapman (at Los Alamos? Livermore?).  
This is not to be confused with the fusion pulse rocket concepts that
have been looked at at Livermore. 
 
The fission fragment rocket consists of large numbers of very thin
carbon wires containing a fissionable isotope, like one of americium. 
The wires are rotated through a core in which they become part of a
critical mass.  The wires are sufficiently thin that fission fragments
can escape with most of their energy. The fragments, which are
travelling at a couple of percent of the speed of light, are funneled
by a magnetic field out a nozzle, providing thrust.  Waste heat
deposited in the wires is radiated when they are outside the core. 
 
The rocket would need about 100 tons of americium.
 
The rocket would not be too well suited to much of the solar system,
as the exhaust velocity is too high and the thrust too low.  It would
be best suited to the outer solar system. 
 
	Paul F. Dietz
	[email protected]

Article: 15057
Newsgroups: sci.space.shuttle
From: [email protected] (Henry Spencer)
Subject: Re: A Fragment of Light Speed
Date: Tue, 14 Sep 1993 17:07:48 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]>
[email protected] (Paul Dietz) writes: 

>The [fission-fragment] rocket would not be too well suited to much
>of the solar system,
>as the exhaust velocity is too high and the thrust too low.  It would
>be best suited to the outer solar system.
 
Almost any high-velocity-low-thrust rocket can be re-optimized for lower
velocities and higher thrust by using its exhaust energy to heat larger
amounts of reaction mass.  Of course, you have to sort out the detailed
design and then decide whether the results are worth the trouble.  In
the limit, the fission-fragment rocket becomes just another nuclear-
thermal rocket, which isn't that exciting.  The question is whether
you can find an intermediate point -- specifically, whether you can
use the fission fragments to heat reaction mass efficiently, which
avoids the reactor-temperature limitations imposed by absorbing the
fission energy within a solid mass and then transferring heat to
the reaction mass.
-- 
"Every time I inspect the mechanism     | Henry Spencer @ U of Toronto Zoology
closely, more pieces fall off."         |  [email protected]  utzoo!henry

Article: 72861
Organization: ESOC European Space Operations Centre
Date: Thu, 16 Sep 1993 16:03:58 CET
From: <[email protected]>
Newsgroups: sci.space
Subject: Pulsed Fission Cycles
 
Thanks for all of the responses to my initial posting, However, I
guess I should have been a little more specific about the nature of
the concept which I have in mind, so here goes. 
 
The idea of obtaining high Isp together with a high thrust (i.e. a
high jet power) from a low mass/small sized engine implies that a high
pressure plasma must be used as part of the working fluid. The
principle of a nuclear pulse rocket is that the generation and
manipulation of this plasma is performed external to the vehicle,
which does away with the sort of heavy and/or sophisticated
containment vessel - equivalent to the combustion chamber of a
chemical rocket - envisaged for the nuclear fission gas core cycle, of
which the "light bulb" engine is but one example. 
 
The plasma is generated in bursts, via a nuclear reaction, and a
"relatively" simple pusher plate is used to absorb some of the
momentum of the expanding fluid, which is, in turn, transfered to the
vehicle via some sort of shock absorber to smooth out the acceleration
loads on the payload. The Orion concept envisaged the use of fission
or fusion bombs - with kiloton or megaton yields - to generate its
pulses, though the basic concept was demonstrated between 1959 and
1960 using a model (now on display in the Smithsonian) driven by
chemical explosives. The VISTA concept envisages the use of an
inertially confined nuclear fusion reaction generated by the
compression of small pellets of H/He isotopes via an array of laser
beams. 
 
What I have in mind is the generation of a fission reaction by the
compression of small amounts of suitably packaged Pu, since I have
reason to believe that such a reaction may be easier to initiate than
a fusion process, give a high yield, and relatively benign end
products. Since the individual pellets could in no way be regarded as
self-standing weapons, and could only be "ignited" in a carefully
controlled way (i.e. essentially zero risk of all or part of the Pu
detonating in storage) the political and safety objections ought to be
significantly reduced, though I don't expect they would ever go away,
due to the psychological impact of the word "Plutonium" ! 
 
Generation of the compression beams is one aspect that I have not
addressed here, however, suffice it to say that there appears to be a
"todays technology" solution which may make the pulsed fission cycle a
technically feasible option in the very near term. 
 
P.S. The responses received so far, together with literature searches,
etc, tend to support my suspicion  that such information is does not
exist in the "public domain"; which is a pity, because the utilization
of such a cycle would, I believe, change our perception of the
difficulties and cost of performing missions beyond LEO in the near to
mid-term future (i.e. 2000 AD to 2030 AD). 
 
P.P.S. For a good overview of the performance and potential of Orion
type cycles, see the Journal of the British Interplanetary Society
(JBIS), Vol. 32, pp 283-310, 1979, for the paper entitled "Nuclear
Pulse Propulsion: A Historical Review of an Advanced Propulsion
Concept", by A.R. Martin and A. Bond. 
 
Dave Salt
Darmstadt, Germany

     "The crowd will follow a leader who marches twenty steps in
      advance; but if he is a thousand steps in front of them, they do
      not see and do not follow him, and any literary freebooter who
      chooses may shoot him with impunity."
        -- Georg Brandes, Danish literary critic (1842 - 1927)

>What I have in mind is the generation of a fission reaction by the
>compression of small amounts of suitably packaged Pu, since I have
>reason to believe that such a reaction may be easier to initiate than
>a fusion process, give a high yield, and relatively benign end
                                          ^^^^^^^^^^^^^^^^^
Relative to what I wonder?  


>products. Since the individual pellets could in no way be regarded as
>self-standing weapons, and could only be "ignited" in a carefully
>controlled way (i.e. essentially zero risk of all or part of the Pu
>detonating in storage) the political and safety objections ought to be
>significantly reduced, though I don't expect they would ever go away,
>due to the psychological impact of the word "Plutonium" ! 

Political: I suppose there's no way to recombine these into a larger chunk
of Pu?  Bullfeathers.

Safety: The chemical toxicity of Pu seems to be ignored here.


- dave

Article: 752
From: [email protected] (Bill Higgins-- Beam Jockey)
Newsgroups: sci.space.tech
Subject: Reading list (was Re: Nuclear Pulse Engines)
Date: 8 Feb 94 23:11:59 -0600
Organization: Fermi National Accelerator Laboratory
 
In article <[email protected]>, "Jon Jeckell,
Mankato State University, MN" <[email protected]> writes: 

>    I am doing a project for graduation on Nuclear Pulse Engines (like Project
> Orion), and I would like as much information on this as possible.  I would 
> also like as much info as possible on related topics as project NERVA (the
> Nuclear thermal rocket) and solar-ion drives, etc.
 
I answered Jon at first by sending him my boilerplate reply and a
chunk of the FAQ.  Then I noticed that we cite a lot of
annoyingly-hard-to-find references under  propulsion.  So I started
typing.  Then I realized that others might like to see this, or maybe
we should spruce up the FAQs-- certainly people ask about Orion often
enough! 
 
For ORION and OTHER NUCLEAR-PULSE PROPULSION get:
 
The Matloff and Mallove book *Interstellar Flight* mentioned in the FAQs
 
*Project Daedalus* by Alan Bond and A.R. Martin
 
*The Curve of Binding Energy* by John McPhee (nontechnical, but one of the
better sources on Orion's history)
 
An article by Freeman Dyson from about 1964 in *Science* called "Death of a
Project" (search other volumes if I've got the wrong year)
 
Dyson's book *Disturbing the Universe*
 
Eugen Saenger's book (may be spelled Sanger) *Space Flight* which has fairly
detailed treatment early of nuclear-pulse
 
*Adventures of a Mathematician* by Stanislaw Ulam has a little bit of Orion
history
 
If you want to do your own modeling, you'll need S. Glasstone's
*Effects of Nuclear Weapons*.
 
I think there's a bit about Livermore people thinking about nuclear
pulse in  Tom Heppenheimer's *The Man-Made Sun* and William Broad's
*Star Warriors*.
 
MORE GENERAL NUCLEAR PROPULSION:
 
Many propulsion textbooks from the golden age of the early Sixties,
when it looked like we were actually going to use some of our crazy
ideas, spend at least a little space on exotic propulsion.  There are
loads of information on NERVA, Rover, Kiwi, and other nuclear-rocket
projects.  *Nuclear Flight* by Kenneth Gantz is one book (but it
spends a lot of time on nuclear AIRPLANES).  There's a
book on nuclear rockets by R. Bussard and R. DeLauer too.
 
Find a library with *Spaceflight* or *Journal of the British
Interplanetary Society* or *Astronautica Acta* and troll the indexes
since 1960.
 
*Air and Space* might be helpful for pop treatments.  (Anybody with
specific citations, chime right in!)
 
For recent work on nuclear propulsion, the American Institute of
Physics has published the proceedings of the  *Symposium on Space
Nuclear Power Systems: 10th anniversary Symposium on Space Nuclear
Power and Propulsion*, edited by  Mohamed S. El-Genk and Mark D.
Hoover.  Actually, they've published books for 8th, 9th, and 10th
symposioa, in three volumes EACH!  The Fermilab library has a standing
order for AIP books and as a result we have all nine volumes here.  If
I took the time to read through them, I would be a very smart man. 
And fun at parties.  Women would find me fascinating.  "Tell me more
about space nuclear power systems, Bill."
 
Ahem.  Sorry, I drifted off there.  Anyway, if Jon can find these
books he'll have a pretty good slice of nuclear propulsion work (as
well as nuclear electricity in space) as it stands in the Eighties and
Nineties.
 
Submarines, flying boats, robots, talking         Bill Higgins
pictures, radio, television, bouncing radar       Fermilab
vibrations off the moon, rocket ships, and        [email protected]
atom-splitting-- all in our time.  But nobody     [email protected]
has yet been able to figure out a music           SPAN:  43009::HIGGINS
holder for a marching piccolo player. 
                     --Meredith Willson, 1948

    
    In a nuclear rocket is the ejected mono-atomic H2 radio-active ?
    
    I was thinking about this the other day, and the question just
    hit me...  How can Mono-atomic Hydrogen (the one normaly used)
    become radio-active when it has no Neutrons !!! ???
    
    No doubt some neutrons will be captured but not enough to make
    much of a difference.
    
    In any case  this means that given the proper conditions, you
    could even use  Nuclear Propultion in Earth-to-Orbit Shuttles.
    With an exaust velocity of 9.1 Km/s (as provided by a Nuclear
    Termal Engine) a SSTO Shuttle with dry mass of 150 Tons would 
    only need 300 tons of mono-atomic H2 propelant.
    
    "Proper conditions" meaning that safety measures would be used
    in order to avoid raining radio-active nuclear core elements
    on top of people if a fatal failure happens ... such as encasing
    the nuclear core elements and using over the Ocean launch and
    landing tracks. And overcoming the inevitable anti-nuclear
    oposition. (-;
    
    Gil
    

re .24
    
>How can Mono-atomic Hydrogen (the one normaly used) become radio-active when
>it has no Neutrons !!! ???
    
    I really don't know but perhaps the hydrogen atom can *gain* a neutron
    and then lose it later by decay. In any case I feel that the bulk of the
    objections would pertain to the presence of the nuclear reactor itself.
    
>    With an exhaust velocity of 9.1 Km/s (as provided by a Nuclear
>    Thermal Engine)
    
    For the record do you have comparative specific impulse figures for a
    nuclear thermal engine vs. an SSME (for example)?
    
>using over the Ocean launch and landing tracks.
    
    Ocean launch track seems more or less obligatory already.
    
    If your new engine were used only for a large one way booster then you
    wouldn't have to worry about landing track (but don't ask me about the
    profusion of nuclear reactors in Earth orbit!).
    
    (A one way booster wouldn't preclude a manned mission though. I can imagine
    a Mars journey where this booster gets you on the way and a much smaller
    vehicle contained within it is the return vehicle. Indeed there may be
    no Earth landing vehicle part of the mission at all if return is via a
    hypothetical LEO space station.)
    
>And overcoming the inevitable anti-nuclear opposition. (-;
    
    I am sceptical that you can do that. Before picking up the gauntlet you
    would at least need to establish that nuclear propulsion met a need that
    cannot otherwise be met. Considering the demise of NASP and the precarious
    position in which DC finds itself and the political colour of the current
    regime I find it hard to believe that your idea would be funded.

    re .-1 (me)
    
    Project Timberwind was looking at this but as far as I know that is an
    ex-project (bereft of funds it has joined the choir invisible etc.).
    
    One of the concerns with the engines that might have come out of that
    project is that the hydrogen (reaction mass) would have picked up small
    amounts of radioactive material (fuel or fission products) before being
    expelled. This was using particle bed technology and I guess that the
    hydrogen gas made direct contact with the particles. (The particles
    were coated to avoid chemical reaction with the hot hydrogen.)
    
    FWIW the projected specific impulse was 1000 seconds (US units) compared
    with typical chemical engines that give an Isp somewhere between 200
    seconds and 400 seconds.
    
    (info from old AvLeak issues)

Article: 2507
From: [email protected] (Allen Thomson)
Newsgroups: sci.space.tech
Subject: Gas Core Reactor/Rockets
Date: Sun, 10 Jul 1994 02:25:32 GMT
Organization: NETCOM On-line Communication Services (408 261-4700 guest)
 
     This was posted to sci.space.tech a couple of weeks ago, but seem
to have gone to bit.limbo. It followed some discussion of the propulsion 
used in the movie 2001 and gas-core nuclear propulsion systems. 
 
***********************************************************************
 
     I checked one of our bibliographic CD ROMs and found some recent
papers on gas core reactors -- these are three which seemed to be
interesting:
 
------------------------------------------------------------------------
 
  Tendencies  of high temperature gas core reactors for NTP and space power
plants development
  GLINIK, RAFAIL A. (NPO Energomash, Moscow, Russia)
  AIAA, SAE, ASME, and ASEE, Joint Propulsion Conference and Exhibit, 29th,
Monterey, CA, June 28-30, 1993. 6 p.
  Publication Date: Jun. 1993      4 Refs.
  Report No.: AIAA PAPER 93-2366
  This  paper  examines  the development tendencies of the high-temperature
gas  phase  fuel  elements  (GPFEs)  and  gas core nuclear reactors (GCRs).
Particular  attention  is  given  to the developent program for the gaseous
fuel  elements  in  an  experimental  pulse  graphite  reactor (IGR) with a
thermal  neutron flux density up to 10 exp 15 t.n./sq cm s. Diagrams of the
reactor, the liquid metal feed system, and the combined gas core reactor are
presented.
 
 
  Magnetic fuel containment in the Gas Core Nuclear Rocket
  KAMMASH, T.; GALBRAITH, D. L. (Michigan Univ., Ann Arbor)
  AIAA, SAE, ASME, and ASEE, Joint Propulsion Conference and Exhibit, 29th,
Monterey, CA, June 28-30, 1993. 5 p. Research supported by DOE.
  Publication Date: Jun. 1993      9 Refs.
  Report No.: AIAA PAPER 93-2368
  The  open  cycle  Gas  Core  Nuclear Rocket (GCR) is often mentioned as a
second generation Nuclear Thermal Propulsion (NTP) system that could make a
round  trip  manned mission to Mars in a few months instead of a few years.
Such  a  capability  is  based on preliminary assessments of its propulsion
performance  as  reflected  in  the high specific impulse and thrust it can
potentially generate. The energy in this device is produced by a fissioning
uranium  plasma  which  heats,  through  radiation, a propellant that flows
around  the  core  and  exits  through a nozzle, thereby converting thermal
energy into thrust. The relative motion between the propellant and the fuel
is a source of hydrodynamic instability which, if not adequately addressed,
could  lead  to  a  serious  loss  of  the  fuel in a very short time. This
instability can, however, be suppressed by placing the system in a magnetic
field with a configuration such that it will not interfere with the primary
function  of  the device. In this paper, we introduce a model with which we
study  such  magnetic  containment and its impact on the performance of the
system. 
 
[Magnetic confinement and mixing inhibition was the concept "Ievlev's" 
g.c.r. was based on.] 
 
 
  In-reactor  testing  of  the  closed  cycle gas core reactor: The Nuclear
Light Bulb concept
  GAUNTT,  R.  O.;  SLUTZ,  S.  A.;  HARMS,  G.  A.;  LATHAM, T. S. (United
Technologies  Research  Center,  East  Hartford, CT.); ROMAN, W. C. (UTRC); 
RODGERS, R. J. (UTRC)
  Sandia National Labs., Albuquerque, NM.
  Publication Date: Oct. 1992      11P.
  Presentation Note: Presented at the 10th Symposium on Space Nuclear Power
and Propulsion, Albuquerque, NM, 10-14 Jan. 1993
  Report No.: DE93-004053; SAND-92-1462C; CONF-930103-24
  The  Nuclear  Light  Bulb (NLB) concept is an advanced closed cycle space
propulsion  rocket  engine  design  that  offers  unprecidented performance
characteristics  in  terms  of  specific  impulse (greater than 1800 s) and
thrust  (greater than 445 kN). The NLB is a gas-core nuclear reactor making
use  of thermal radiation from a high temperature U-plasma core to heat the
hydrogen  propellant  to  very  high  temperatures  (greater  than 4000 K).
Analyses  performed  in  support of the design of in-reactor tests that are
planned  to  be  performed  in  the Annular Core Research Reactor (ACRR) at
Sandia   National  Laboratories  in  order  to  demonstrate  the  technical
feasibility  of this advanced concept are described. The tests will examine
the  stability  of  a  hydrodynamically  confined fissioning U-plasma under
steady  and  transient  conditions.  Testing  will  also  involve  study of
propellant  heating  by  thermal  radiation  from  the plasma and materials
performance  in  the nuclear environment of the NLB. The analyses presented
include neutronic performance studies and U-plasma radiation heat-transport
studies  of  small vortex-confined fissioning U-plasma experiments that are
irradiated  in  the  ACRE.  These  analyses  indicate  that  high  U-plasma
temperatures  (4000  to 9000 K) can be sustained in the ACRE for periods of
time on the order of 5 to 20 s. These testing conditions are well suited to
examine the stability and performance requirements necessary to demonstrate
the feasibility of this concept.
 
------------------------------------------------------------------------
 
     The paper by Glinik piqued my interest, so I did a bit of BIBLIOINT 
and came up with the following titles.  Making the perhaps unjustified 
assumption that there is a common theme underlying these papers and 
patents, it looks as Glinik and his associates have worked on the 
superconducting solenoid for the confinement system of the g.c.r., and 
perhaps also on the "first wall" for the reactor.  The items dealing with 
superconducting magnet construction, strength, and irradiation effects 
might be consistent with either a g.c.r. or a fusion reactor.  However, 
the 1000 atm. pressure mentioned in the last abstract is a fairly typical 
number for the reaction chamber of a g.c.r. but not (I think)  for a 
magnetically confined fusion system. 
 
     Further supporting this interpretation is the presence of V.N. 
Khazov as a coauthor: Khazov is one of two authors of the articles on 
nuclear rocket engines ["Yadernyy Raketnyy Dvigatel'"] and gas-core 
nuclear rocket engines ["Gazofaznyy Ya. R. D."] in the 1985 
Entsiklopediya Kosmonavtika which was edited by V.P. Glushko. NPO 
Energomash, with which both Glinik and Khazov seem to be associated 
currently, is the major rocket engine design and manufacturing facility 
which produces, for example, the RD-170/171/180 family and the RD-701 
tripropellant engine. 
 
 
Basic Patent (No,Kind,Date): SU 1056779 A1 901030
   METHOD  OF  RESTORING  WORKING  CHARACTERISTICS  OF  SUPERCONDUCTOR-BASE
      WINDINGS OPERATING UNDER IRRADIATION CONDITIONS (English)
Author  (Inventor):  NASKIDASHVILI  I  A  ;  MARTKOPLISHVILI  G S ;
     CHACHANIDZE  R  V ; STEPANOV G B ; GLINIK R A ; KHAZOV V N
 
  Effect of magnetic field on the plastic deformation on aluminum at 4.2 K
  Gostishchev, V. I.; Glinik, R. A.; Petrovskii, M. L.; Khazov, V. N.
   Institute of Solid State Physics and Semiconductors, Belorussian Academy
of Sciences
  JETP Lett. 30(2),92-96 (20 JUL. 1979)
 
    HIGH FORCE SUPERCONDUCTING CURRENT RAIL - HAS INTERLAYER WITH HARDENING
    MATERIAL BETWEEN CONDUCTOR AND YOKE
Author (Inventor): GLINIK R A; GOSTISCHE V I; KHAZOV V N
 
    Electromagnet heavy current coil mfr. - by winding coil with extra pure
    aluminium strip with glass fabric insulation between turns, and
    impregnated with epoxy.
Author (Inventor): GLINIK R A; KHAZOV V N; ASTASHENKO N N
    SU 729664      A     800425     8050   (Basic)
 
    Superconducting rails electric conductivity measuring sample - has
    insulated inserts to separate loops of bus formed into zigzag and uses
    sum of signals from loops to fix parameters of bus
Author (Inventor): GLINIK R A; GOSTISHCHE V I; KHAZOV V N
    SU 628762      A     901030     9123   (Basic)
 
  (INSTALLATION POUR ESSAIS MECANIQUES DE MATERIAUX DANS UN MILIEU DE
HAUTES PRESSIONS FRAGILES)
  EN RUSSE
  GLINIK R A; DUBROVSKIJ K E; MATVEEV E M; MURAV'EV E V
  Journal: ZAVODSK. LAB.,  1973, 39 (9) 1136-1137
  RESULTATS   DE   DETERMINATION   DE   CONTRAINTES   LORS  DE  LA  FLEXION
D'ECHANTILLONS DE GRAPHITE SOUS PRESSION JUSQU'A 1000 ATM